Exploring the effects of added sugar labels on food purchasing behaviour in Australian parents: An online randomised controlled trial

Background Evidence of the effects of front-of-pack added sugar labelling remains limited, especially for foods other than sugary drinks. More information is needed about which labels are likely to be most effective in reducing intended purchases of products with higher added sugar content in realistic contexts to inform policymakers' decisions. Objective To determine the impact of added sugar labels on intended purchases of high sugar breakfast cereals, yoghurt, and non-alcoholic beverages. Methods Australian parents who were regular purchasers of relevant product categories completed an online parallel randomised controlled trial from 31 August 2020 to 13 February 2021. Participants selected their intended purchase from 10 products in each of packaged beverages, breakfast cereal, and yoghurt categories after randomisation to one of seven added sugar labelling conditions in current use or under consideration by the Australian Government. Logistic regressions assessed differences between intervention and control conditions in the odds of intended purchases of a high sugar product. Results 2825 eligible participants were randomised with 2582 valid surveys analysed (Control n = 367; 'Nutrition Information Panel (NIP) with Added Sugar' n = 364; 'Teaspoons of Sugar' n = 369; 'Warning' n = 371; 'Health Star Rating (HSR) using Total Sugar' n = 368; 'HSR with Added Sugar' n = 371; 'Sugar in the Ingredients List' n = 372). No consistent effects were found on intended purchases of high sugar products overall or within product categories for any of the tested labels compared to controls (overall, 'NIP with Added Sugar': OR 1.00 [95%CI 0.83,1.20]; 'Teaspoons of Sugar': 0.94[0.80,1.11]; 'Warning': 1.10[0.93,1.30]; 'HSR with Total Sugar': 1.01[0.85,1.21]; 'HSR with Added Sugar': 1.09[0.92,1.30]; 'Sugar in the Ingredients List': 1.01[0.85,1.21]). Conclusions Findings reinforce the importance of ensuring nutrition labelling policies are introduced as part of a suite of interventions to influence both consumer and manufacturer behaviour.